The Best AR-15 Lower Parts Kits for the Money

In this guide, we'll be covering the best AR-15 lower parts kits.

Though lower parts kits are often overlooked, there are actually significant differences between the various kits on the market today—and quality counts. You don't want something like a small detent or spring to be what takes down your rifle.

That's why we've chosen the highest quality kits, made by manufacturers with extreme dedication to detail and quality control.

Best AR-15 Lower Parts Kit

We'll cover more about what's needed to complete an AR-15 lower and why we chose these options below, but first, here's our list of the best AR-15 lower parts kit options:

Kits and Parts to Finish Your Lower

As you probably noticed in the table above, most lower parts kits don't include all of the parts you need to complete an AR-15 lower receiver. This is because many AR-15 builders like to choose their pistol grip, trigger, buffer assembly, and stock separately.

The Brownells MOE kit includes everything you need, but the BCM Stock Kit can be used to round out the BCM Enhanced and CMMG Kits.

What Parts are Needed for a Complete AR-15 Lower?

So you have a stripped AR-15 lower that you're needing to complete, what other parts should you get?

There's a pretty long list of parts that are needed. For first time builders, it will seem overwhelming, but don't worry! Building an AR-15 lower is actually quite simple and requires few tools.

Full AR-15 Lower Parts List

Before you look at this picture of all the parts, let me say I can barely put together IKEA furniture but have managed to build numerous AR-15 lowers. Despite being the opposite of mechanically inclined, I usually manage to get it done in about 30 minutes.

Here's a full list of all the parts needed to complete an AR-15 Lower:

Hammer

Hammer Spring

Trigger

Trigger Spring

Hammer & Trigger Pivot Pins

Disconnector

Disconnector Spring

Bolt Catch

Bolt Catch Plunger

Bolt Catch Spring

Bolt Catch Roll Pin

Pivot Pin

Buffer Retainer

Buffer Retainer Spring

Magazine Catch Button

Magazine Catch Spring

Magazine Catch

Take Down Pin

Selector

Selector Detent

Selector Detent Spring

Trigger Guard

Trigger Guard Roll Pin

Trigger Guard Screw

Pistol Grip

Grip Screw

Grip Screw Washer

Take Down/Pivot Pin Detent

Take Down/Pivot Pin Detent Spring

Buffer Tube/Receiver Extension (Not Shown)

Buffer Spring (Not Shown)

Buffer (Not Shown)

Stock (Not Shown)

The diagram above shows the BCM Enhanced Lower Parts Kit, which I highly recommend and many agree to be one of the best lower parts kits available. BCM makes exceptionally high-quality products and this kit offers the:

You can also be a lot more confident that everything will arrive and no parts will be missing. I've personally had missing parts when buying lower parts kits from cheaper manufacturers, and I'd rather pay a few bucks more than have to deal with contacting the retailer or manufacturer.

Quality

Difference between parts really comes into play when you buy a kit that includes a trigger, pistol grip, or buffer assembly.

I've purchased the below CMMG lower parts kit in the past that is cheaper than the BCM one I recommend.

What I did NOT do, was use the pistol grip or trigger that came with it. The trigger would likely be serviceable, though I don't think it's as nice as the BCM PNT or ALG Defense Combat Trigger. The pistol grip, on the other hand, feels incredibly cheap, flimsy, and uncomfortable.

If your budget is super tight, you could use this kit, but I'll bet you'll want to be upgrading the trigger and pistol grip ASAP.

I will say that the two times I've bought this kit, everything showed up, and I've had no issues with the parts of it I've actually used. It's also nice to have an extra trigger/hammer and pistol grip lying around—just in case.

The Best Lower Parts Kit for Beginners

If you just want to buy one kit that comes with everything you need, then the Brownells MOE kit is likely the best lower parts kit for you.